1. Field of the Invention
The present invention relates to an optical coherence tomography (OCT) apparatus, and an OCT apparatus control method.
2. Description of the Related Art
An eye portion tomographic image capturing apparatus such as an OCT (Optical Coherence Tomography) can three-dimensionally observe the state inside a tissue, for example, a retinal layer. An example of the OCT is a TD-OCT (Time domain OCT) that is a combination of a broadband light source and a Michelson interferometer. The TD-OCT obtains depth resolution information by measuring an interference light between a backscattered light of a reference arm and a backscattered light of a signal arm while changing an optical path of the reference arm. Also, there is known an SD-OCT (Spectral domain OCT) that uses a spectroscope instead of changing an optical path of a reference arm, detects a dispersed light by a line sensor, and acquires an interferogram. Also, there is known an SS-OCT (Swept Source OCT) based on a technique that measures a spectral interference by a single-channel photodetector by using a high-speed wavelength-swept light source as a light source (U.S. Pat. No. 5,321,501). The OCT has been developed as described above, and development is being conducted to image a plurality of areas by a single device. For example, the department of ophthalmology is beginning to image an anterior eye portion and a posterior eye portion by a single device.
In the OCT, as an optical path length difference between a reference light and a measurement light becomes smaller, that is, as an optical path length becomes closer to the same position (coherence gate position), a better image quality is obtained. It has been known that discloses changing the optical path length difference between a reference light and a measurement light according to an SN of an image (Japanese Patent Application Laid-Open No. 2008-154941).
However, when a plurality of areas is imaged, since an imaging screen is not always suitable for a target to be imaged, rapid imaging is impossible.